美国流感季提早且检测阳性率同比飙升10倍，但报道未给出任何公司级需求或业绩增量

It may only be October, but flu season is in full swing.

The percent of positive tests for influenza soared 10-fold in the week ended Oct. 10 from the same period a year earlier, the US Centers for Disease Control and Prevention reported on Friday. The last time the rate was at a comparable level at this point in the season was also an outlier, in 2019, right before the Covid-19 pandemic.

In addition to the virus hitting earlier and harder, the current vaccine isn’t completely matched to stop it. There’s also a geographic anomaly. The season normally begins in October or November in the southeast and picks up as it spreads across the US in the winter. This time, the virus emerged in late summer and is established nationwide, with the highest activity levels now in the West.

“Pathogens like the flu like to keep us guessing,” said Braylee Weets, an analyst with Georgetown University’s Health Security Operations Center.

It’s an important issue every year for the country and a wide swath of the economy. The severity of flu season can impact health insurers like Humana Inc., pharmacies and drug-benefit managers including CVS Health Corp. and hospitals such as such as HCA Healthcare Inc. This year it’s also having an unintended impact on politics, as James Talarico, a Democrat running for Senate in Texas, was embroiled in a controversy after he contracted the flu and was out of the public eye for more than a week before the US midterm elections.

Marlene Wolfe, an assistant professor of environmental health at Emory University, said the change from a year ago is significant. WastewaterSCAN, a project she helps lead that monitors infectious diseases in municipal systems, has already found the virus in 64% of samples across the country. That’s more than triple the percentage recorded last October.

“Last year we did not see seasonal flu onset until early December,” Wolfe said. “We’re seeing that kind of earlier onset, earlier increase and greater percentage of samples that are positive for flu right now.”

It could be worse. The virus that’s currently circulating is influenza A, one of the two main varieties that’s well understood and often less virulent. Together with influenza B, it typically infects as many as 51 million people in the US a year. While the number early infections remains low, as 5% of tests came in positive compared with 0.5% a year ago, the virus has room to grow from its early start.

While infections caused by the circulating H1N1 strain aren’t normally severe, Andrew Pekosz, with Johns Hopkins’ Bloomberg School of Public Health, said the current vaccine may not be a perfect match for it.

“What’s interesting about that H1N1 virus is it has a couple of mutations that we predict will make the vaccine strain a little less effective,” he said.

Raising Awareness

Hospitals and public health departments are advised to prepare for the flu season by Oct. 1 each year, Weets said, but early infections may raise public awareness and spur earlier flu clinics. Those are important, she said, as immunization still offers protection. It could be particularly helpful if other strains emerge.

“It’s about preventing what we can by getting vaccinated, taking care of your family and people around you and just being a little more aware at this time of year,” she said.

While it’s too early to predict the severity of this year’s flu season, it can have a meaningful impact. Outbreaks drive up hospitalizations and medical costs, while boosting demand for over-the-counter cold and flu medicines, antiviral drugs and immunizations.

Millions of people are routinely vaccinated against the flu every year, something experts said they expect to continue. Nearly half of American adults received last season’s shot, according to the CDC, and Pekosz said he hasn’t seen a major change in terms of willingness to get it.

Still, it’s an issue, with vaccine hesitancy debates persisting around the country. The US Department of Health and Human Services also changed its recommendations for the childhood vaccine schedule in January, and ceased broad endorsements for routine immunizations like influenza.

Experts are closely watching demand for Moderna Inc.’s mRNA shot, dubbed mFLUSIVA, which was approved in August after regulatorswent back and forth on the company’s application. It was backed for adults over the age of 50, though it’s unclear how widely it’s being administered.

Healthcare providers are telling people to get their flu shot as soon as possible, given the virus’ potential severity and changes in strain that can occur throughout the season. With vaccination rates dipping for measles, mumps, and rubella, health departments are encouraging families to get a full suite of protection when they go to the doctor’s office.

They want to avoid a repeat of last season, when the CDC estimatedin March that there were at least 28 million flu-related illnesses and 22,000 deaths. That outbreak was driven in large part by a mutation of the H3N2 strain. By the end of May, the agency recorded high severity flu-like illnesses across all age groups.

“I’m hoping that people remember how bad the flu was from last year’s experience, and maybe take that to heart this year when the vaccine is available, which of course it is right now,” Pekosz said.